0
点赞
收藏
分享

微信扫一扫

org.springframework.beans.BeanUtils

WikongGuan 2022-08-19 阅读 98

 

org.springframework.beans.BeanUtils的一个demo。可以很优雅的实现将父类字段的值copy到子类中

下面例子的输出结果(子类使用父类的toString方法,有点意思吧):

true
Person{name='people'}

import org.springframework.beans.BeanUtils;

public class Test {

public static void main(String[] args) {
Person person = new Person("people");
Male male = newcopyProperties(person, male);

System.out.println(Male.class.isInstance(male));
System.out.println(male);
}
}

class Person {
private String name;

public Person() {
}

public Person(String name) {
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
'}';
}
}

class Male extends Person {
private String necklace;

public Male() {
}

public Male(String name) {
super(name);
}

public String getNecklace() {
return necklace;
}

public void setNecklace(String necklace) {
this.necklace = necklace;
}
}

 

 

org.springframework.beans.BeanUtils
源码解析:
使用的是反射:

/**
* Copy the property values of the given source bean into the target bean.
* <p>Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* <p>This is just a convenience method. For more complex transfer needs,
* consider using a full BeanWrapper.
* @param source the source bean
* @param target the target bean
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
public static void copyProperties(Object source, Object target) throws BeansException {
copyProperties(source, target, null, (String[]) null);
}

 

/**
* Copy the property values of the given source bean into the given target bean.
* <p>Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* @param source the source bean
* @param target the target bean
* @param editable the class (or interface) to restrict property setting to
* @param ignoreProperties array of property names to ignore
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
private static void copyProperties(Object source, Object target, Class<?> editable, String... ignoreProperties)
throws BeansException {

Assert.notNull(source, "Source must not be null");
Assert.notNull(target, "Target must not be null");

Class<?> actualEditable = target.getClass();
if (editable != null) {
if (!editable.isInstance(target)) {
throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
"] not assignable to Editable class [" + editable.getName() + "]");
}
actualEditable =ignore
}
PropertyDescriptor[] targetPds =actualEditable);
List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);

fortargetPds) {
Method writeMethod = targetPd.getWriteMethod();
if (writeMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {
PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
if (sourcePd != null) {
Method readMethod = sourcePd.getReadMethod();
if (readMethod != null &&
ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {
try {
if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
readMethod.setAccessible(true);
}
Object value = readMethod.invoke(source);
if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
writeMethod.setAccessible(true);
}
writeMethod.invoke(target, value);
}
catch (Throwable ex) {
throw new FatalBeanException(
"Could not copy property '" + targetPd.getName() + "' from source to target", ex);
}
}
}
}
}
}

 



举报

相关推荐

0 条评论